Flat cap

In electrical and electronic circuits, an unforeseen oscillation may occur at a specific frequency due to design flaws or wiring defects, which interferes with functionality. This phenomenon is synonymous with abnormal oscillation.

In feedback control circuits with on-off control, when the controlled variable exceeds the target value and the manipulated variable switches from on to off, the controlled variable may then fall below the target value. When the manipulated variable is switched back from off to on, the controlled variable may again exceed the target value. This phenomenon may repeat, causing the controlled variable to oscillate up and down around the target value.